using SFP+ past 10 meters

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digity

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Jun 3, 2017
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I want to route a 10 Gb link that is about 50 feet. I understand SFP+ limitation is ~33 feet (10 meters), so what issues can I expect to experience if going past 10 meters?

P.S. - I can't afford 10Base-T switches at the moment
 

digity

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Jun 3, 2017
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DACs are somewhat limited, but fiber has much higher limits. Get some SR transceivers and OM3 fiber patch cable. 50ft is no problem.
Thanks for the quick reply! Reading your response I realize I don't understand the 10 Gb space as much as I thought I did. So I get 10Gb NICs that accept SR transceivers instead of SFP+ transceivers and get OM3 fiber cables instead of DAC copper cables?
 

ttabbal

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Mar 10, 2016
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SFP+ can take the transceivers directly. Something like this..

Cisco SFP-10G-SR 10GBASE-SR SFP+ Transceiver | FS.COM

Some NICs and switches are picky about the transceivers. That store can get you the kind you need if that's an issue. Mellanox NICs tend not to care, but Intel does, for example.

The fiber then plugs into the transceivers and you're off.
 
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digity

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SFP+ can take the transceivers directly. Something like this..

Cisco SFP-10G-SR 10GBASE-SR SFP+ Transceiver | FS.COM

Some NICs and switches are picky about the transceivers. That store can get you the kind you need if that's an issue. Mellanox NICs tend not to care, but Intel does, for example.

The fiber then plugs into the transceivers and you're off.
Nice! I assume this cable is all I need - 20m (66ft) LC UPC to LC UPC Duplex OM3 Armored PVC (OFNR) Patch Cable | FS.COM. If not, what spec of cable should I be looking for?
 
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Evan

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Thanks for the quick reply! Reading your response I realize I don't understand the 10 Gb space as much as I thought I did. So I get 10Gb NICs that accept SR transceivers instead of SFP+ transceivers and get OM3 fiber cables instead of DAC copper cables?
Exactly :)
Fs.com to get cheap and compatible SR sfp and LC-LC OM3/4 fiber and your good to go
 
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ttabbal

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digity

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Outstanding! You all took a ton of stress out of this project for me. Thanks so much!

Sent from my SM-G955U using Tapatalk
 

Evan

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That's right! FS.COM is a good place to buy modules and cables.
Yeah I use them when I want an SFP coded for something non-Cisco etc, if you know what your looking for also eBay etc but they are helpful and if you just want a one stop shop it works.

They ate now sticking 40G and I think 100G stuff at good prices as well, not experience with how it work as only ever using that at work and then it's all OEM or don't touch it.
 

pc_doom

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I want to route a 10 Gb link that is about 50 feet. I understand SFP+ limitation is ~33 feet (10 meters), so what issues can I expect to experience if going past 10 meters?

P.S. - I can't afford 10Base-T switches at the moment
You must mean SFP+ cable limitation is 10 meters, not SFP+ module. Since SFP+ cable is only suitable for very short distance transmission, but SFP+ module and cables can support longer distance. As other guys mentioned here, you can directly go to FS.COM to get SFP module and fiber patch cable, but you have to get your 10G NIC card first, so you would know which SFP module is compatible.
 
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digity

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Actually, I'm still curious... What happens when you go past 10 meters with SFP+ DAC?

Sent from my SM-G955U using Tapatalk
 

Evan

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You can't, DAC is the SFP and cable in one part, I guess nobody makes one longer than 10m
Presume the limitation is both the practicality of long fixed length cables with attached electrics and also the 2.5w limit on sfp, copper connections use a lot of power.
 
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digity

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So the NICs I'm considering are listed below because they're known to work well with FreeNAS. I know SR SFP+ was recommended but how does that differ from CR SFP+? I ask because it looks like they're easier to find and cheaper
  1. Chelsio T520-SO-CR
  2. Chelsio T520-CR
  3. Intel X710-da2
  4. Intel X540-da2 / X540-sr2
  5. Chelsio T420-CO-SR
 

i386

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sr = Short Reach (using optic fibers)
cr = Copper, direct atached cable (DAC), this is NOT 10gbase-t (the "normal lan" connector)

DACs are available as passive cables supporting distances up to 10feet/3meters for in rack cabling or as active cables (electronics amplifying the signals) up to 15 meter for inter rack cabling.

Passive DACs are the cheapest options for 10gbe, but support only short distances.
Active DACs are not worth the price: transceivers + fibers are a little bit more expensive but support 50+ meters.

Edit: passive DACs can be up to 7meters
 

digity

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sr = Short Reach (using optic fibers)
cr = Copper, direct atached cable (DAC), this is NOT 10gbase-t (the "normal lan" connector)

DACs are available as passive cables supporting distances up to 10feet/3meters for in rack cabling or as active cables (electronics amplifying the signals) up to 15 meter for inter rack cabling.

Passive DACs are the cheapest options for 10gbe, but support only short distances.
Active DACs are not worth the price: transceivers + fibers are a little bit more expensive but support 50+ meters.

Edit: passive DACs can be up to 7meters
Now I'm confused... earlier in the thread it was recommended to get the Cisco SFP-10G-SR compatible SFP+ transceiver with the 20 meter LC UPC to LC UPC Duplex OM3 cable, but if SR stands for short reach than the Cisco SFP-10G-SR is only for short distances and not up to 300 meters as listed in the specs?
 

digity

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It's all relative: 300 meters is short, compared to 10+ km lr sfp+ transceivers can do
gotcha! so I can ONLY procure a NIC that is SR if I'm to use the Cisco SFP-10G-SR transceiver and 20 meter LC UPC to LC UPC Duplex OM3 cable for my 50 foot run?